refactor: remove bundled Claude Code binary support

- Remove all bundled/sidecar binary functionality
- Delete build scripts for fetching and building Claude executables
- Simplify binary detection to only support system installations
- Update UI to remove bundled installation options
- Update build configuration and documentation

README.md

@@ -253,9 +253,9 @@ brew install pkg-config
    bun run tauri build
    
    # The built executable will be in:
-   # - Linux: src-tauri/target/release/bundle/
-   # - macOS: src-tauri/target/release/bundle/
-   # - Windows: src-tauri/target/release/bundle/
+   # - Linux: src-tauri/target/release/
+   # - macOS: src-tauri/target/release/
+   # - Windows: src-tauri/target/release/
    ```
 
 4. **Platform-Specific Build Options**
@@ -265,11 +265,6 @@ brew install pkg-config
    bun run tauri build --debug
    ```
    
-   **Build without bundling (creates just the executable)**
-   ```bash
-   bun run tauri build --no-bundle
-   ```
-   
    **Universal Binary for macOS (Intel + Apple Silicon)**
    ```bash
    bun run tauri build --target universal-apple-darwin
@@ -324,7 +319,7 @@ The build process creates several artifacts:
   - `.msi` installer (Windows)
   - `.exe` installer (Windows)
 
-All artifacts are located in `src-tauri/target/release/bundle/`.
+All artifacts are located in `src-tauri/target/release/`.
 
 ## 🛠️ Development